FRICTION REDUCING TOOL

Description

[0001] The present invention relates to a friction reducing tool suitable for use in drilling applications. In one aspect the present invention relates to a tool having a multipart rotatable outer component wherein the parts may be secured together by rods insertable through a groove in the main body part of the drill string component and a tool incorporating rollers having positive roller containment.

[0002] It is known in the industry to provide a tool in which an outer rotatable portion is formed in multiple parts, which are secured together about the tool. Typically, a recess is provided in the main body portion of the tool and the multiple parts are secured about the main body portion within the recess so as to be rotatable thereabout. Typically, the multiple portions are fastened together by bolts or other similar fastening means. Often this requires projecting flanges which may cause obstruction. Further, under extreme loads the multiple portions could separate, leaving parts of the tool obstructing a well.

[0003] It is also known to provide rollers about the periphery of a tool to minimise friction. Typically, such rollers are inserted into a cavity in the tool from the exterior and a pin is inserted to secure the roller in place. Under severe load conditions the pin can shear and the roller and pin may drop out of the tool and obstruct the well.

[0004] US-A-1801294 describes a sucker rod guide having ball bearings mounted in sockets in a housing, protruding slightly outside the housing.

[0005] WO 95/10585 describes a drill pipe tubing and casing protector having a plastic sleeve formed in two parts.

[0006] WO 96/34173 describes a reducing friction tool with rollers.

[0007] It is an object of the present invention to overcome these problems or at least to provide the public with a useful choice.

[0008] According to a first aspect of the invention there is provided a friction reducing tool for drilling applications comprising a generally tubular body portion having a cavity in a side wall thereof which accommodates a roller secured by an axle, the roller being provided with projections at either end which locate within overhang portions of the body portion so that should the axle break the roller cannot pass out of the cavity to the exterior of the body portion.

[0009] Preferably the friction reducing tool includes an inner component securable to or about an oil field tubular with said body portion being rotatable about the inner component, wherein the body portion is formed in multiple parts secured together by rods and is located within an annular recess in the inner component and wherein a groove is provided in the inner component adjacent the recess to enable a rod to be inserted when the parts of the body portion are assembled about the recess.

[0010] The groove is preferably angled downwards towards the recess so that the rod deflects as it is inserted into apertures in the parts and, when in place, abuts against thrust faces of the drill string component.

[0011] The tool preferably includes a plastic sleeve for securement about an oil field tubular and first and second collars to secure the plastic sleeve to the oil field tubular at either end wherein the body portion is securable about the plastic sleeve between the collars in use.

[0012] The invention will now be described with reference to the accompanying drawings, in which:

Figure 1

shows a partial perspective view of an outer component of a friction reducing tool.

Figure 2

shows a partial cross-sectional view of the outer component shown in Figure 1.

Figure 3:

shows a partial cross-sectional view along the axis of the tool.

Figure 4:

shows a partial cross-sectional view of the outer component.

Figure 5:

shows an exploded view of a roller and roller cavity.

Figure 6:

shows insertion of a rod to secure the parts of an outer component together.

Figure 7:

shows a perspective view of the groove which guides the rod during the insertion operation shown in figure 6.

Figure 8:

shows an embodiment incorporating a plastics bearing having longitudinal channels.

Figure 9:

shows a further embodiment incorporating a plastics sleeve.

Best mode for carrying out the invention

[0013] Referring firstly to figures 1 to 5 there is shown a friction reducing tool 1 comprising an inner component 2 and a rotatable outer component 3. Outer component 3 includes a plastic bearing 3c and is rotatable with respect to inner component 2 to reduce rotational friction.

[0014] A plurality of rollers 4 are provided in three banks about the periphery of rotatable component 3 within cavities 10 to reduce axial drag. Outer rotatable component 3 is divided into two parts 3a and 3b which, during assembly, are inter-engaged about inner component 2 within recess 16 (see figure 7) and secured in place by rods 15 passing through apertures in inter-engaging tongue portions 5 and 6.

[0015] Each roller 4 is provided with extensions 7 at each end, which, in use, are located within a respective cavity 8. Overhangs 9 prevent roller 4 from leaving cavity 10 should axle 11 shear under high load conditions. As shown in figure 2 the diameter of the bore through roller 4 increases towards the ends of the roller to reduce sheer forces on axle 11 at the ends of the roller.

[0016] To assemble the banks of rollers each roller must be inserted from the interior of outer section 3 and when extensions 7 are located within cavity 8, pin 11 is inserted to secure each roller in place. Pin 11 may be secured in place by welding 12 or other suitable means.

[0017] From figure 1 it will be seen that outer part 3a includes tongues 5 which inter-engage with tongues 6 of outer part 3b. A rod is first passed through apertures in interengaged tongues of outer parts 3a and 3b to join the halves together in a hinged manner. The hinged assembly is then placed within recess 16 and tongues 5 and 6 brought into engagement (as shown in figure 1). Outer parts 3a and 3b are secured together by placing a rod through aperture 13.

[0018] It is important that no part of the drill string component is released to obstruct a well. There is thus provided a groove 14 to facilitate insertion of rod 15 to secure parts 3a and 3b together (see figure 7). As shown diagrammatically in figure 7 parts 3a and 3b are interengaged within recess 16 of body portion 2 with aperture 13 aligned with groove 14. Rod 15 is then guided by groove 14 into aperture 13 to secure parts 3a and 3b together. Once the rod 15 is inserted a grub screw 17 may be inserted to retain pin 15 in place. As is shown diagrammatically in figure 7 rod 15 is deflected as it is inserted within aperture 13 so that it would be extremely difficult for rod 15 to dislodge. Further, as it would be rare for rod 15 to be aligned with groove 14, the chance of rod 15 separating is further minimised.

[0019] Preferably groove 14 is provided in the top end of body portion 2 so that rod 15 will not be forced against groove 14 by the force of gravity. The drill string component is preferably formed of steel although the rollers 4 could be formed of suitable plastics materials.

[0020] Referring to figure 8 an embodiment incorporating a thermoplastics bearing 21 between an outer section 20 and a main body portion 22 is shown conceptually in cross section. The thermoplastics bearing 21 incorporates rectangular channels 23 to facilitate lubrication.

[0021] Referring now to figure 9 there is shown an alternative embodiment in which a plastics sleeve 30 is secured directly to drill string 31 by stop collars 32 and 33. Outer section 34 is of the same construction as outer section 3 described above and is secured about plastics sleeve 30.

[0022] The interior surface of outer component 34 is preferably hard faced and precision ground to reduce friction between outer component 34 and plastics sleeve 30.

[0023] In use plastics sleeve 30 may be slid over one end of drill pipe 31.
Alternatively, where a hinged or multi-part sleeve is employed, the sleeve may be placed about drill pipe 31. A first collar 32 may then be secured about sleeve 30 at one end thereof. The collars may be of single or multipart construction. Outer component 34 may then be placed about plastics sleeve 30 and a rod inserted within bore 35 to secure the parts together (as previously described). Stop collar 33 may then be secured about the other end of plastics sleeve 30 to secure plastics sleeve 30 to drill pipe 31 and retain outer component 34 between stop collars 32 and 33.

[0024] Although this invention has been described in relation to a component for use with a drill string it will be appreciated that the principles of the invention may be applied to a component for installing casing or in other drilling applications. The generic term "oil field tubular" is used to refer to tubular components such as drill string or casing.

[0025] It will be appreciated that the present invention provides an arrangement for mounting rollers which minimises the likelihood of parts of a drill string component obstructing a well. Further, the invention provides a means of reliably securing together multipart outer components which provides strength and minimises the risk of components obstructing a well.

[0026] Although this invention has been described by way of example it is to be appreciated that improvements and/or modifications may be made thereto without departing from the scope of the invention as defined in the appended claims.

Claims

1. A friction reducing tool (1) for drilling applications comprising a generally tubular body portion (3) having a cavity (10) in a side wall thereof which accommodates a roller (4) secured by an axle (11), characterised in that the roller is provided with projections (7) at either end thereof which locate within overhang portions (9) of the body portion, so that should the axle break the roller cannot pass out of the cavity to the exterior of the body portion.

2. A tool as claimed in claim 1 wherein the projections (7) are in the form of tubular extensions at either end of the roller (4).

3. A tool as claimed in claim 1 or 2 wherein the overhang portions (9) are substantially complementary to the shape of the projections (7).

4. A tool as claimed in any one of the preceding claims wherein the roller (4) has a bore therethrough to accommodate the axle (11), the diameter of the bore increasing towards the outer ends thereof to reduce shear forces on the axle.

5. A tool as claimed in any one of the preceding claims wherein a plurality of cavities (10) are provided about the periphery of the tool (1).

6. A tool as claimed in any one of the preceding claims wherein a plurality of rollers (4) are provided in each cavity (10).

7. A friction reducing tool as claimed in any one of the preceding claims having an inner component (2) securable to or about an oil field tubular with said body portion (3) being rotatable about the inner component in use, wherein the body portion is formed in multiple parts (3a, 3b) secured together by rods (15) and is located within an annular recess (16) in the inner component, and wherein a groove (14) is provided in the inner component adjacent the recess to enable a rod to be inserted whilst parts of the body portion are assembled about the recess.

8. A tool as claimed in claim 7 wherein the groove (14) is inclined downwardly from one end of the inner component (2) to the recess (16).

9. A tool as claimed in claim 7 or 8 wherein each part (3a, 3b) of the body portion (3) is provided with interengaging tongues (5, 6) so that the parts may be joined in a hinged manner.

10. A tool as claimed in any one of claims 7 to 9 wherein the body portion (3) is formed in two parts (3a, 3b).

11. A tool as claimed in any one of the claims 7 to 10 wherein a plastics sleeve (30) is provided between the inner component (2) and the body part (3).

12. A tool as claimed in any one of claims 7 to 11 wherein the inner component (2) is a sub-assembly having couplings for engagement to sections of a drill pipe.

13. A friction reducing tool as claimed in any one of claims 1 to 11, including a plastics sleeve (30) for securement about an oil field tubular (31) and first and second collars (32, 33) to secure the plastics sleeve to the oil field tubular at either end thereof wherein the body portion (34) is securable about the plastics sleeve between the collars in use.

14. A tool as claimed in claim 13 wherein the body portion (34) is formed in a plurality of parts which is secured together by rods passing through apertures in interengaging faces of the parts.

15. A tool as claimed in claim 13 or 14 wherein the interior faces of the parts are hard faced and ground.

16. A method of assembling a friction reducing tool as claimed in claim 13 about an oil field tubular comprising:

i) placing a plastics sleeve (30) about the oil field tubular (31);

ii) securing a collar (32) about one end of the plastics sleeve;

iii) positioning the body portion (34) about the plastics sleeve; and

iv) securing a collar (33) about the other end of the plastics sleeve to retain the body portion about the plastics sleeve between the collars.

17. A method as claimed in claim 16 wherein the body portion (34) is formed in a plurality of parts which are secured together by inserting a rod through apertures in interengaging faces of the parts when the parts are brought together in step iii.

Ansprüche

1. Reibungsminderungswerkzeug (1) für Bohranwendungen, das einen allgemein tubulären Körperabschnitt (3) mit einem Hohlraum (10) in einer Seitenwand davon umfasst, der eine an einer Achse (11) befestigte Rolle (4) aufnimmt, dadurch gekennzeichnet, dass die Rolle an beiden Enden mit Vorsprüngen (7) versehen ist, die sich in Überhangabschnitten (9) des Körperabschnitts befinden, so dass die Rolle im Falle eines Bruchs der Achse nicht aus dem Hohlraum hinaus zur Außenseite des Körperabschnitts geraten kann.

2. Werkzeug nach Anspruch 1, wobei die Vorsprünge (7) die Form von tubulären Verlängerungen an beiden Enden der Rolle (4) haben.

3. Werkzeug nach Anspruch 1 oder 2, wobei die Überhangabschnitte (9) im Wesentlichen komplementär zur Gestalt der Vorsprünge (7) sind.

4. Werkzeug nach einem der vorherigen Ansprüche, wobei durch die Rolle (4) eine Bohrung zur Aufnahme der Achse (11) verläuft, wobei der Durchmesser der Bohrung in Richtung auf die äußeren Enden davon zunimmt, um Scherkräfte an der Achse zu reduzieren.

5. Werkzeug nach einem der vorherigen Ansprüche, wobei eine Mehrzahl von Hohlräumen (10) um die Peripherie des Werkzeugs (1) vorgesehen ist.

6. Werkzeug nach einem der vorherigen Ansprüche, wobei eine Mehrzahl von Rollen (4) in jedem Hohlraum (10) vorgesehen ist.

7. Reibungsminderungswerkzeug nach einem der vorherigen Ansprüche mit einer Innenkomponente (2), die an einem oder um ein Ölfeldrohr befestigt werden kann, wobei der Körperabschnitt (3) beim Gebrauch um die Innenkomponente gedreht werden kann, wobei der Körperabschnitt in mehreren Teilen (3a, 3b) ausgebildet ist, die durch Stäbe (15) aneinander befestigt sind und sich in einer ringförmigen Aussparung (16) in der Innenkomponente befinden, und wobei eine Rille (14) in der Innenkomponente neben der Aussparung vorgesehen ist, damit ein Stab eingeführt werden kann, während Teile des Körperabschnitts um die Aussparung montiert sind.

8. Werkzeug nach Anspruch 7, wobei die Rille (14) von einem Ende der Innenkomponente (2) nach unten zur Aussparung (16) hin geneigt ist.

9. Werkzeug nach Anspruch 7 oder 8, wobei jedes Teil (3a, 3b) des Körperabschnitts (3) mit ineinander greifenden Zungen (5, 6) versehen ist, so dass die Teile aneinander angelenkt werden können.

10. Werkzeug nach einem der Ansprüche 7 bis 9, wobei der Körperabschnitt (3) in zwei Teilen (3a, 3b) ausgebildet ist.

11. Werkzeug nach einem der Ansprüche 7 bis 10, wobei eine Plastikhülse (30) zwischen der Innenkomponente (2) und dem Körperteil (3) vorgesehen ist.

12. Werkzeug nach einem der Ansprüche 7 bis 11, wobei die Innenkomponente (2) eine Unterbaugruppe mit Kupplungen für den Eingriff in Abschnitte eines Bohrrohres ist.

13. Reibungsminderungswerkzeug nach einem der Ansprüche 1 bis 11 mit einer Plastikhülse (30) zur Befestigung um ein Ölfeldrohr (31) und einem ersten und einem zweiten Kragen (32, 33) zum Befestigen der Plastikhülse an beiden Enden des Ölfeldrohres, wobei der Körperabschnitt (34) beim Gebrauch um die Plastikhülse zwischen den Kragen befestigt werden kann.

14. Werkzeug nach Anspruch 13, wobei der Körperabschnitt (34) in einer Mehrzahl von Teilen ausgebildet ist, die durch Stäbe aneinander befestigt sind, die durch Löcher in ineinander greifenden Flächen der Teile passieren.

15. Werkzeug nach Anspruch 13 oder 14, wobei die Innenflächen der Teile hartaufgetragen und geschliffen sind.

16. Verfahren zum Montieren eines Reibungsminderungswerkzeugs nach Anspruch 13 um ein Ölfeldrohr, das die folgenden Schritte umfasst:

i) Platzieren einer Plastikhülse (30) um das Ölfeldrohr (31);

ii) Befestigen eines Kragens (32) um ein Ende der Plastikhülse;

iii) Positionieren des Körperabschnitts (34) um die Plastikhülse; und

iv) Befestigen eines Kragens (33) um das andere Ende der Plastikhülse, um den Körperabschnitt um die Plastikhülse zwischen den Kragen zu halten.

17. Verfahren nach Anspruch 16, wobei der Körperabschnitt (34) in einer Mehrzahl von Teilen ausgebildet ist, die durch Einführen eines Stabs durch Löcher in ineinander greifenden Flächen der Teile aneinander befestigt sind, wenn die Teile in Schritt iii zusammengebracht werden.

Revendications

1. Outil de réduction du frottement (1) pour des applications de forage comprenant une partie de corps généralement tubulaire (3) avec une cavité (10) dans une paroi latérale correspondante, recevant un rouleau (4) fixé par un essieu (11), caractérisé en ce que le rouleau comporte des saillies (7) au niveau d'une extrémité correspondante, agencées dans des parties en porte-à-faux (9) de la partie de corps, de sorte qu'en cas d'une cassure de l'essieu, le rouleau ne peut pas passer hors de la cavité vers l'extérieur de la partie de corps.

2. Outil selon la revendication 1, dans lequel les saillies (7) ont la forme d'extensions tubulaires au niveau d'une extrémité du rouleau (4).

3. Outil selon les revendications 1 ou 2, dans lequel les parties en porte-à-faux (9) ont une forme pratiquement complémentaire à la forme des saillies (7).

4. Outil selon l'une quelconque des revendications précédentes, dans lequel le rouleau (4) comporte un alésage le traversant pour recevoir l'essieu (11), le diamètre de l'alésage étant accru vers les extrémités externes correspondantes pour réduire les forces de cisaillement appliquées à l'essieu.

5. Outil selon l'une quelconque des revendications précédentes, dans lequel plusieurs cavités (10) sont agencées autour de la périphérie de l'outil (1).

6. Outil selon l'une quelconque des revendications précédentes, dans lequel plusieurs rouleaux (4) sont agencés dans chaque cavité (10).

7. Outil de réduction du frottement selon l'une quelconque des revendications précédentes, comportant un composant interne (2) pouvant être fixé sur un élément tubulaire d'un champ de pétrole avec ladite partie de corps (3), ou autour de celui-ci, pouvant tourner autour du composant interne en service, la partie de corps comprenant de multiples parties (3a, 3b) assemblées par des tiges (15) et étant agencée dans un évidement annulaire (16) dans le composant interne, une rainure (14) étant agencée dans le composant interne près de l'évidement pour permettre l'insertion d'une tige, les parties de la partie de corps étant assemblés autour de l'évidement.

8. Outil selon la revendication 7, dans lequel la rainure (4) est inclinée vers le bas à partir d'une extrémité du composant interne (2) vers l'évidement (16).

9. Outil selon les revendications 7 ou 8, dans lequel chaque partie (3a, 3b) de la partie de corps (3) comporte des languettes à engagement mutuel (5, 6), de sorte que les parties peuvent être reliées par articulation.

10. Outil selon l'une quelconque des revendications 7 à 9, dans lequel la partie de corps (3) comprend deux parties (3a, 3b).

11. Outil selon l'une quelconque des revendications 7 à 10, dans lequel un manchon en plastique (30) est agencé entre le composant interne (2) et la partie de corps (3).

12. Outil selon l'une quelconque des revendications 7 à 11, dans lequel le composant interne (2) est sous-assemblé et comporte des raccords destinés à s'engager dans des sections d'un tube de forage.

13. Outil de réduction du frottement selon l'une quelconque des revendications 1 à 11, englobant un manchon en plastique (30) destiné à être fixé autour d'un élément tubulaire d'un champ de pétrole (31), et des premier et deuxième colliers (32, 33) pour fixer le manchon en plastique sur l'élément tubulaire du champ de pétrole au niveau d'une extrémité correspondante, la partie de corps (34) pouvant être fixée en service autour du manchon en plastique entre les colliers.

14. Outil selon la revendication 13, dans lequel la partie de corps (34) comprend plusieurs parties assemblées par des tiges traversant des ouvertures dans des faces à engagement mutuel des parties.

15. Outil selon les revendications 13 ou 14, dans lequel les faces internes des parties sont soumises à un rechargement dur et à une rectification.

16. Procédé d'assemblage d'un outil de réduction du frottement selon la revendication 13 autour d'un élément tubulaire d'un champ de pétrole, comprenant les étapes ci-dessous:

(i) agencement d'un manchon en plastique (30) autour de l'élément tubulaire du champ de pétrole (31);

(ii) fixation d'un collier (32) autour d'une extrémité du manchon en plastique;

(iii) positionnement de la partie de corps (34) autour du manchon en plastique; et

(iv) fixation d'u collier (33) autour de l'autre extrémité du manchon en plastique pour retenir la partie de corps autour du manchon en plastique entre les colliers.

17. Procédé selon la revendication 16, dans lequel la partie de corps (34) comprend plusieurs parties assemblées par insertion d'une tige à travers des ouvertures dans les faces à engagement mutuel des parties lors de l'assemblage de celles-ci au cours de l'étape iii.

Drawing